Highly available data-processing network functions for radio-based networks

ABSTRACT

Disclosed are various embodiments that provide highly available data-processing network functions for radio-based networks. In one embodiment, a tunnel host consistently routes network traffic associated with a range of network addresses in a radio-based network to a first instance of a data-processing network function instead of a second instance of the data-processing network function. A problem with the first instance of the data-processing network function is then detected. Additional network traffic associated with the range of network addresses is redirected from the first instance of the data-processing network function to the second instance of the data-processing network function.

BACKGROUND

5G is the fifth-generation technology standard for broadband cellularnetworks, which is planned eventually to take the place of thefourth-generation (4G) standard of Long-Term Evolution (LTE). 5Gtechnology will offer greatly increased bandwidth, thereby broadeningthe cellular market beyond smartphones to provide last-mile connectivityto desktops, set-top boxes, laptops, Internet of Things (IoT) devices,and so on. Some 5G cells may employ frequency spectrum similar to thatof 4G, while other 5G cells may employ frequency spectrum in themillimeter wave band. Cells in the millimeter wave band will have arelatively small coverage area but will offer much higher throughputthan 4G.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, with emphasis instead being placed uponclearly illustrating the principles of the disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1A is a drawing of an example of a communication network that isdeployed and managed according to various embodiments of the presentdisclosure.

FIG. 1B is a drawing of an example of a networked environment thatimplements highly available network functions in radio-based networksand associated core networks according to various embodiments of thepresent disclosure.

FIG. 2A illustrates an example of a networked environment including acloud provider network and further including various provider substrateextensions of the cloud provider network, which may be used in variouslocations within the communication network of FIG. 1, according to someembodiments of the present disclosure.

FIG. 2B depicts an example of cellularization and geographicdistribution of the communication network of FIG. 1 for providing highlyavailable user plane functions (UPFs).

FIG. 3 illustrates an example of the networked environment of FIG. 2Aincluding geographically dispersed provider substrate extensionsaccording to some embodiments of the present disclosure.

FIG. 4 is a schematic block diagram of the networked environment of FIG.2A according to various embodiments of the present disclosure.

FIG. 5 is a flowchart illustrating one example of functionalityimplemented as portions of a tunnel control plane executed in acomputing environment in the networked environment of FIG. 4 accordingto various embodiments of the present disclosure.

FIG. 6 is a flowchart illustrating one example of functionalityimplemented as portions of a route reflector executed in a computingenvironment in the networked environment of FIG. 4 according to variousembodiments of the present disclosure.

FIG. 7 is a flowchart illustrating one example of functionalityimplemented as portions of a tunnel host executed in a computingenvironment in the networked environment of FIG. 4 according to variousembodiments of the present disclosure.

FIG. 8 is a schematic block diagram that provides one exampleillustration of a computing environment employed in the networkedenvironment of FIG. 4 according to various embodiments of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure relates to implementing highly availabledata-processing network functions in radio-based networks, such as 4Gand 5G radio access networks, or portions of such radio-based networks,and associated core networks using cloud provider networkinfrastructure. One example of a data-processing network function is theuser plane function (UPF) in 5G networks. The UPF is the interconnectpoint between mobile infrastructure and the data network, and the UPFserves as the protocol data unit session anchor point for providingmobility within and between different radio access networks. The UPF isexecuted to apply policies to customer network traffic and then forwardthe network traffic via the user data plane as appropriate. The UPF issimilar to a router in that network traffic passes through it ratherthan being terminated on it. The UPF also performs applicationdetection, implements network slicing and quality-of-servicerequirements, and monitors traffic for billing purposes.

In some implementations, the UPF is required to scale to handle up tomillions of Internet-facing internet protocol (IP) addresses, which maybe contiguous subnetworks that are routed to the same destination. Insome implementations, all network traffic for a specific end user deviceis required to go through a single UPF, and thousands of user devicesmay be mapped to an individual UPF. In the event that a UPF fails, allsubsequent network traffic from particular user devices should be sentto a replacement UPF for the particular user devices. Also, variousembodiments may be deployed at different network levels, includingregions, local zones, edge locations, and cell sites.

Various embodiments of the present disclosure introduce a software-basedsubnetwork load balancer to route network traffic to specific networkfunctions, such as UPFs, and to handle failover and migration betweennetwork functions. The failover for network functions may be required tobe handled in less than one second, and in under 100 milliseconds insome scenarios.

As one skilled in the art will appreciate in light of this disclosure,certain embodiments may be capable of achieving certain advantages,including some or all of the following: (1) improving availability incommunications networks by allowing for failover and transition betweendata-processing network functions such as UPFs with minimal delay; (2)improving flexibility in communications networks by allowingdata-processing network functions and load balancers for thosedata-processing network functions to be implemented in software, therebyallowing the data-processing network functions and load balancers to beexecuted in cloud provider networks and at different locations inradio-based networks and associated core networks; (3) improving theoperation of communications networks by facilitating scaling ofdata-processing network functions such as UPFs in response toutilization, latency, or other metrics; and so forth.

Among the benefits of the present disclosure is the ability of acellularized control plane, which controls operation of a radio-basednetwork that operates at least partially using cloud providerinfrastructure, to deploy and chain network functions together acrossdifferent physical sites and to manage failover across physical sites todeliver a high availability UPF. Cellularization of the control planerefers to having multiple independently operatable copies of the controlplane (referred to as “cells”), such that an individual control planefailure is prevented from impacting all deployments. According to thepresent disclosure, network functions organized into microservices worktogether to provide end-to-end connectivity (referred to in places as“network function stacks”). One set of network functions are part of aradio network, running in cell towers and performing wireless signal toIP conversion. Other network functions run in large data centersperforming subscriber related business logic and routing IP traffic tothe internet and back. For applications to use the new capabilities of5G such as low latency communication and reserved bandwidth, both ofthese types of network functions need to work together to appropriatelyschedule and reserve wireless spectrum, and perform real time computeand data processing.

The presently disclosed techniques provide edge location hardware (asdescribed further below) integrated with network functions that runacross the entire network, from cell sites to internet break-outs, andorchestrate the network functions across these sites to provide highavailability. Specifically, within each control plane infrastructurecell, multiple redundant network function stacks can be provisioned,with the control plane cell shifting traffic to secondary stacks asneeded to provide the required availability. These redundant networkfunction stacks can be provisioned across different ones or combinationsof edge locations, customer data centers, and cloud provideravailability zones. This enables an entirely new set of applicationsthat have strict quality-of-service (QoS) requirements, fromfactory-based IoT, to augmented reality (AR), to virtual reality (VR),to game streaming, to autonomous navigation support for connectedvehicles, that previously could not run on a mobile network.

The described “elastic 5G” service provides and manages all thehardware, software and network functions, required to build a network,and can orchestrate network functions across different physical sites asdescribed herein. In some embodiments the network functions may bedeveloped and managed by the cloud service provider, however thedescribed control plane can manage network functions across a range ofproviders so that customers can use a single set of APIs to call andmanage their choice of network functions on cloud infrastructure. Theelastic 5G service beneficially automates the creation of an end-to-end5G network, from hardware to network functions, thus reducing the timeto deploy and the operational cost of operating the network. Byproviding APIs that expose network capabilities, the disclosed elastic5G service enables applications to simply specify the desired QoS asconstraints and then deploys and chains the network functions togetherto deliver an end-to-end network slice that reflects the networkcharacteristics requested by the software application, as well asmanaging failover to provide the level of availability required by thesoftware application.

The present disclosure describes embodiments relating to the creationand management of a cloud native 5G core and/or a cloud native 5G RAN,and associated control plane components. Cloud native refers to anapproach to building and running applications that exploits theadvantages of the cloud computing delivery model such as dynamicscalability, distributed computing, and high availability (includinggeographic distribution, redundancy, and failover). Cloud native refersto how these applications are created and deployed to be suitable fordeployment in a public cloud. While cloud native applications can be(and often are) run in the public cloud, they also can be run in anon-premises data center. Some cloud native applications can becontainerized, for example having different parts, functions, orsubunits of the application packaged in their own containers, which canbe dynamically orchestrated so that each part is actively scheduled andmanaged to optimize resource utilization. These containerizedapplications can be architected using a microservices architecture toincrease the overall agility and maintainability of the applications. Ina microservices architecture, an application is arranged as a collectionof smaller subunits (“microservices”) that can be deployed and scaledindependently from one another, and which can communicate with oneanother over a network. These microservices are typically fine-grained,in that they have specific technical and functional granularity, andoften implement lightweight communications protocols. The microservicesof an application can perform different functions from one another, canbe independently deployable, and may use different programminglanguages, databases, and hardware/software environment from oneanother. Decomposing an application into smaller services beneficiallyimproves modularity of the application, enables replacement ofindividual microservices as needed, and parallelizes development byenabling teams to develop, deploy, and maintain their microservicesindependently from one another. A microservice may be deployed using avirtual machine, container, or serverless function, in some examples.The disclosed core and RAN software may follow a microservicesarchitecture such that the described radio-based networks are composedof independent subunits that can be deployed and scaled on demand.

Turning now to FIG. 1A, shown is an example of a communication network100 that is deployed and managed according to various embodiments of thepresent disclosure. The communication network 100 includes a radio-basednetwork 103, which may correspond to a cellular network such as afourth-generation (4G) Long-Term Evolution (LTE) network, afifth-generation (5G) network, a 4G-5G hybrid core with both 4G and 5GRANs, or another network that provides wireless network access. Theradio-based network 103 may be operated by a cloud service provider fora public telecommunications provider or for an enterprise or otherorganization. Various deployments of radio-based network 103 can includeone or more of a core network and a RAN network, as well as a controlplane for running the core and/or RAN network on cloud providerinfrastructure. As described above, these components can be developed ina cloud native fashion, for example using a microservices architecture,such that centralized control and distributed processing is used toscale traffic and transactions efficiently. These components may bebased on the 3GPP specifications by following an applicationarchitecture in which control plane and user plane processing isseparated (CUPS Architecture).

The radio-based network 103 provides wireless network access to aplurality of wireless devices 106, which may be mobile devices or fixedlocation devices. In various examples, the wireless devices 106 mayinclude smartphones, connected vehicles, IoT devices, sensors, machinery(such as in a manufacturing facility), hotspots, and other devices. Thewireless devices 106 are sometimes referred to as user equipment (UE) orcustomer premises equipment (CPE).

The radio-based network 103 can include a RAN that provides the wirelessnetwork access to the plurality of wireless devices 106 through aplurality of cells 109. Each of the cells 109 may be equipped with oneor more antennas and one or more radio units that send and receivewireless data signals to and from the wireless devices 106. The antennasmay be configured for one or more frequency bands, and the radio unitsmay also be frequency agile or frequency adjustable. The antennas may beassociated with a certain gain or beamwidth in order to focus a signalin a particular direction or azimuthal range, potentially allowing reuseof frequencies in a different direction. Further, the antennas may behorizontally, vertically, or circularly polarized. In some examples, aradio unit may utilize multiple-input, multiple-output (MIMO) technologyto send and receive signals. As such, the RAN implements a radio accesstechnology to enable radio connection with wireless devices 106, andprovides connection with the radio-based network's core network.Components of the RAN include a base station and antennas that cover agiven physical area, as well as required core network items for managingconnections to the RAN.

Data traffic is often routed through a fiber transport networkconsisting of multiple hops of layer 3 routers (e.g., at aggregationsites) to the core network. The core network is typically housed in oneor more data centers. The core network typically aggregates data trafficfrom end devices, authenticates subscribers and devices, appliespersonalized policies, and manages the mobility of the devices beforerouting the traffic to operator services or the Internet. A 5G Core forexample can be decomposed into a number of microservice elements withcontrol and user plane separation. Rather than physical networkelements, a 5G Core can comprise virtualized, software-based networkfunctions (deployed for example as microservices) and can therefore beinstantiated within Multi-access Edge Computing (MEC) cloudinfrastructures. The network functions of the core network can include aUser Plane Function (UPF), Access and Mobility Management Function(AMF), and Session Management Function (SMF), described in more detailbelow. For data traffic destined for locations outside of thecommunication network 100, network functions typically include afirewall through which traffic can enter or leave the communicationnetwork 100 to external networks such as the Internet or a cloudprovider network. Note that in some embodiments, the communicationnetwork 100 can include facilities to permit traffic to enter or leavefrom sites further downstream from the core network (e.g., at anaggregation site or radio-based network 103).

The UPF provides an interconnect point between the mobile infrastructureand the Data Network (DN), i.e. encapsulation and decapsulation ofGeneral Packet Radio Service (GPRS) tunneling protocol for the userplane (GTP-U). The UPF can also provide a session anchor point forproviding mobility within the RAN, including sending one or more endmarker packets to the RAN base stations. The UPF can also handle packetrouting and forwarding, including directing flows to specific datanetworks based on traffic matching filters. Another feature of the UPFincludes per-flow or per-application QoS handling, including transportlevel packet marking for uplink (UL) and downlink (DL), and ratelimiting. The UPF can be implemented as a cloud native network functionusing modern microservices methodologies, for example being deployablewithin a serverless framework (which abstracts away the underlyinginfrastructure that code runs on via a managed service).

The AMF can receive the connection and session information from thewireless devices 106 or the RAN and can handle connection and mobilitymanagement tasks. For example, the AMF can manage handovers between basestations in the RAN. In some examples the AMF can be considered as theaccess point to the 5G core, by terminating certain RAN control planeand wireless device 106 traffic. The AMF can also implement cipheringand integrity protection algorithms.

The SMF can handle session establishment or modification, for example bycreating, updating and removing Protocol Data Unit (PDU) sessions andmanaging session context within the UPF. The SMF can also implementDynamic Host Configuration Protocol (DHCP) and IP Address Management(IPAM). The SMF can be implemented as a cloud native network functionusing modern microservices methodologies.

Various network functions to implement the radio-based network 103 maybe deployed in distributed computing devices 112, which may correspondto general-purpose computing devices configured to perform the networkfunctions. For example, the distributed computing devices 112 mayexecute one or more virtual machine instances that are configured inturn to execute one or more services that perform the network functions.In one embodiment, the distributed computing devices 112 are ruggedizedmachines that are deployed at each cell site.

By contrast, one or more centralized computing devices 115 may performvarious network functions at a central site operated by the customer.For example, the centralized computing devices 115 may be centrallylocated on the premises of the customer in a conditioned server room.The centralized computing devices 115 may execute one or more virtualmachine instances that are configured in turn to execute one or moreservices that perform the network functions.

In one or more embodiments, network traffic from the radio-based network103 is backhauled to one or more core computing devices 118 that may belocated at one or more data centers situated remotely from thecustomer's site. The core computing devices 118 may also perform variousnetwork functions, including routing network traffic to and from thenetwork 121, which may correspond to the Internet and/or other externalpublic or private networks. The core computing devices 118 may performfunctionality related to the management of the communication network 100(e.g., billing, mobility management, etc.) and transport functionalityto relay traffic between the communication network 100 and othernetworks.

Moving on to FIG. 1B, shown is an example of a networked environment 150providing highly available user plane functions (UPFs) for radio-basednetworks 103 (FIG. 1A). In particular, the networked environment 150illustrates how network traffic is routed from the network 121, such asthe Internet, to individual UPFs 153 a and 153 b. From the UPFs 153, thenetwork traffic can be forwarded to individual user devices on theradio-based network 103 (FIG. 1A).

To begin, the route advertiser 156 advertises routes for blocks ofnetwork addresses to the network 121. These network addresses may be,for example, IPv4 addresses, IPv6 addresses, or other types of networkaddresses. In one example, the route advertiser 156 exchanges routinginformation using border gateway protocol (BGP) to other autonomoussystems on the network 121. Alternatively, the routing information maybe exchanged by API calls. Accordingly, network traffic on the network121 that is directed to these blocks of addresses will be received atthe elastic network interface 159 a, e.g., by way of a network tunnel.The network prefixes to advertise and the endpoints to use may beconfigured in the route advertiser 156 by the tunnel control plane 162.In the event of a large scale outage that impairs a part of thenetworked environment 150 such as a region or zone, the route advertiser156 may be configured to reroute the network traffic to a failover zoneor region. This can be automated by health checks or triggered by anapplication programming interface (API) call.

The elastic network interface 159 a will in turn direct the networktraffic to a plurality of tunnel hosts 165 a, 165 b, . . . 165N. Theelastic network interface 159 b spreads the connections among two ormore of the tunnel hosts 165 to ensure redundancy in the event that anysingle tunnel host 165 fails. If a tunnel host 165 fails, networktraffic flows assigned to that tunnel host 165 (e.g., by flow-basedhashing) are redirected by the elastic network interface 159 a whenhealth checks indicate the failure. In such situations, the endpointdevices should retry the connection and a reasonable number of flows maybe reassigned onto different paths while waiting for health checks toindicate the failure. The UPFs 153 a, 153 b send route advertisements(e.g., using BGP advertisements or API calls) to the tunnel hosts 165for the tunnel hosts 165 to determine to which UPF 153 each networkaddress should be routed, and the tunnel hosts 165 should consistentlysend the network traffic to the same UPF 153.

The route reflectors 168 a, 168 b are executed to gather routinginformation from the UPFs 153 in order to distribute this information totunnel hosts 165. In one embodiment, this allows individual UPFs 153 tohave two peers at all times, while providing the fleet of tunnel hosts165 the flexibility to scale arbitrarily without requiring customerconfiguration changes. In one embodiment, the route reflectors 168establish BGP peering sessions with the UPFs 153 over an elastic networkinterface 159 a in a virtual private cloud network operated by thecustomer. In other embodiments, other routing protocols or APIs may beused.

When using a routing protocol, the route reflectors 168 may advertise adefault route to the network 121 via the elastic network interface 159a. The route reflectors 168 may be launched and managed by the tunnelcontrol plane 162. The state for each route reflector 168 can bemaintained in a data table for each tunnel control plane 162 to allowthe route reflectors 168 to self-configure when they are launched. Routereflectors 168 may be notified when to update state by a messaging queueand may periodically reconcile their state in the case of a missedupdate via direct lookup of the configuration table. The routereflectors 168 may provide an API that allows the tunnel hosts 165 tomake long polls to the route reflectors 168 to retrieve route updates asrapidly as possible. These routes may reflect which network rangesshould go to which UPFs 153.

The tunnel hosts 165 may be responsible for routing inbound networkpackets to the appropriate UPF 153 using the routing rules retrievedfrom the route reflectors 168 and routing the outbound traffic back tothe network 121. The tunnel hosts 165 may use two elastic networkinterfaces 159 a and 159 b. The elastic network interface 159 receivesnetwork traffic from the network 121 and sends network traffic back tothe network 121 on behalf of the UPF 153. In one embodiment, the elasticnetwork interface 159 a filters to only send traffic for the networkaddress ranges configured for the particular tunnel hosts 165.

The elastic network interface 159 b may face the UPFs 153 and may be thedefault route for the private network that includes the UPFs 153. Alltraffic leaving the UPF 153 that does not have a more specific route inthe private network will be directed to the elastic network interface159 b and then passed to the network 121 via the tunnel hosts 165. Inthe inbound direction toward the UPF 153, the elastic network interface159 b may use an overlay override feature to direct network traffic tothe UPF 153 associated with the specific route. This is more powerfulthan simply using a layer 2 address, as the overlay address override maynot be limited to a local subnet.

The life cycle of the tunnel hosts 165 may be managed by the tunnelcontrol plane 162 to launch the appropriate number of tunnel hosts 165and to scale up and down as desired. The configuration to run eachtunnel host 165 may be obtained directly or indirectly from the routereflectors 168 along with the routing rules. The tunnel control plane162 includes a control plane that translates API calls to configuringthese various components, including tunnel hosts 165 and routereflectors 168.

FIG. 2A illustrates an example of a networked environment 200 includinga cloud provider network 203 and further including various providersubstrate extensions of the cloud provider network 203, which may beused in various locations within the communication network of FIG. 1,according to some embodiments. A cloud provider network 203 (sometimesreferred to simply as a “cloud”) refers to a pool of network-accessiblecomputing resources (such as compute, storage, and networking resources,applications, and services), which may be virtualized or bare-metal. Thecloud can provide convenient, on-demand network access to a shared poolof configurable computing resources that can be programmaticallyprovisioned and released in response to customer commands. Theseresources can be dynamically provisioned and reconfigured to adjust tovariable load. Cloud computing can thus be considered as both theapplications delivered as services over a publicly accessible network(e.g., the Internet, a cellular communication network) and the hardwareand software in cloud provider data centers that provide those services.

The cloud provider network 203 can provide on-demand, scalable computingplatforms to users through a network, for example, allowing users tohave at their disposal scalable “virtual computing devices” via theiruse of the compute servers (which provide compute instances via theusage of one or both of central processing units (CPUs) and graphicsprocessing units (GPUs), optionally with local storage) and block storeservers (which provide virtualized persistent block storage fordesignated compute instances). These virtual computing devices haveattributes of a personal computing device including hardware (varioustypes of processors, local memory, random access memory (RAM),hard-disk, and/or solid-state drive (SSD) storage), a choice ofoperating systems, networking capabilities, and pre-loaded applicationsoftware. Each virtual computing device may also virtualize its consoleinput and output (e.g., keyboard, display, and mouse). Thisvirtualization allows users to connect to their virtual computing deviceusing a computer application such as a browser, application programminginterface (API), software development kit (SDK), or the like, in orderto configure and use their virtual computing device just as they would apersonal computing device. Unlike personal computing devices, whichpossess a fixed quantity of hardware resources available to the user,the hardware associated with the virtual computing devices can be scaledup or down depending upon the resources the user requires.

As indicated above, users can connect to virtualized computing devicesand other cloud provider network 203 resources and services, andconfigure and manage telecommunications networks such as 5G networks,using various interfaces 206 (e.g., APIs) via intermediate network(s)212. An API refers to an interface and/or communication protocol betweena client device 215 and a server, such that if the client makes arequest in a predefined format, the client should receive a response ina specific format or cause a defined action to be initiated. In thecloud provider network context, APIs provide a gateway for customers toaccess cloud infrastructure by allowing customers to obtain data from orcause actions within the cloud provider network 203, enabling thedevelopment of applications that interact with resources and serviceshosted in the cloud provider network 203. APIs can also enable differentservices of the cloud provider network 203 to exchange data with oneanother. Users can choose to deploy their virtual computing systems toprovide network-based services for their own use and/or for use by theircustomers or clients.

The cloud provider network 203 can include a physical network (e.g.,sheet metal boxes, cables, rack hardware) referred to as the substrate.The substrate can be considered as a network fabric containing thephysical hardware that runs the services of the provider network. Thesubstrate may be isolated from the rest of the cloud provider network203, for example it may not be possible to route from a substratenetwork address to an address in a production network that runs servicesof the cloud provider, or to a customer network that hosts customerresources.

The cloud provider network 203 can also include an overlay network ofvirtualized computing resources that run on the substrate. In at leastsome embodiments, hypervisors or other devices or processes on thenetwork substrate may use encapsulation protocol technology toencapsulate and route network packets (e.g., client IP packets) over thenetwork substrate between client resource instances on different hostswithin the provider network. The encapsulation protocol technology maybe used on the network substrate to route encapsulated packets (alsoreferred to as network substrate packets) between endpoints on thenetwork substrate via overlay network paths or routes. The encapsulationprotocol technology may be viewed as providing a virtual networktopology overlaid on the network substrate. As such, network packets canbe routed along a substrate network according to constructs in theoverlay network (e.g., virtual networks that may be referred to asvirtual private clouds (VPCs), port/protocol firewall configurationsthat may be referred to as security groups). A mapping service (notshown) can coordinate the routing of these network packets. The mappingservice can be a regional distributed look up service that maps thecombination of overlay internet protocol (IP) and network identifier tosubstrate IP so that the distributed substrate computing devices canlook up where to send packets.

To illustrate, each physical host device (e.g., a compute server, ablock store server, an object store server, a control server) can havean IP address in the substrate network. Hardware virtualizationtechnology can enable multiple operating systems to run concurrently ona host computer, for example as virtual machines (VMs) on a computeserver. A hypervisor, or virtual machine monitor (VMM), on a hostallocates the host's hardware resources amongst various VMs on the hostand monitors the execution of VMs. Each VM may be provided with one ormore IP addresses in an overlay network, and the VMM on a host may beaware of the IP addresses of the VMs on the host. The VMMs (and/or otherdevices or processes on the network substrate) may use encapsulationprotocol technology to encapsulate and route network packets (e.g.,client IP packets) over the network substrate between virtualizedresources on different hosts within the cloud provider network 203. Theencapsulation protocol technology may be used on the network substrateto route encapsulated packets between endpoints on the network substratevia overlay network paths or routes. The encapsulation protocoltechnology may be viewed as providing a virtual network topologyoverlaid on the network substrate. The encapsulation protocol technologymay include the mapping service that maintains a mapping directory thatmaps IP overlay addresses (e.g., IP addresses visible to customers) tosubstrate IP addresses (IP addresses not visible to customers), whichcan be accessed by various processes on the cloud provider network 203for routing packets between endpoints.

As illustrated, the traffic and operations of the cloud provider networksubstrate may broadly be subdivided into two categories in variousembodiments: control plane traffic carried over a logical control plane218 and data plane operations carried over a logical data plane 221.While the data plane 221 represents the movement of user data throughthe distributed computing system, the control plane 218 represents themovement of control signals through the distributed computing system.The control plane 218 generally includes one or more control planecomponents or services distributed across and implemented by one or morecontrol servers. Control plane traffic generally includes administrativeoperations, such as establishing isolated virtual networks for variouscustomers, monitoring resource usage and health, identifying aparticular host or server at which a requested compute instance is to belaunched, provisioning additional hardware as needed, and so on. Thedata plane 221 includes customer resources that are implemented on thecloud provider network (e.g., computing instances, containers, blockstorage volumes, databases, file storage). Data plane traffic generallyincludes non-administrative operations such as transferring data to andfrom the customer resources.

The control plane components are typically implemented on a separate setof servers from the data plane servers, and control plane traffic anddata plane traffic may be sent over separate/distinct networks. In someembodiments, control plane traffic and data plane traffic can besupported by different protocols. In some embodiments, messages (e.g.,packets) sent over the cloud provider network 203 include a flag toindicate whether the traffic is control plane traffic or data planetraffic. In some embodiments, the payload of traffic may be inspected todetermine its type (e.g., whether control or data plane). Othertechniques for distinguishing traffic types are possible.

As illustrated, the data plane 221 can include one or more computeservers, which may be bare metal (e.g., single tenant) or may bevirtualized by a hypervisor to run multiple VMs (sometimes referred toas “instances”) or microVMs for one or more customers. These computeservers can support a virtualized computing service (or “hardwarevirtualization service”) of the cloud provider network 203. Thevirtualized computing service may be part of the control plane 218,allowing customers to issue commands via an interface 206 (e.g., an API)to launch and manage compute instances (e.g., VMs, containers) for theirapplications. The virtualized computing service may offer virtualcompute instances with varying computational and/or memory resources. Inone embodiment, each of the virtual compute instances may correspond toone of several instance types. An instance type may be characterized byits hardware type, computational resources (e.g., number, type, andconfiguration of CPUs or CPU cores), memory resources (e.g., capacity,type, and configuration of local memory), storage resources (e.g.,capacity, type, and configuration of locally accessible storage),network resources (e.g., characteristics of its network interface and/ornetwork capabilities), and/or other suitable descriptivecharacteristics. Using instance type selection functionality, aninstance type may be selected for a customer, e.g., based (at least inpart) on input from the customer. For example, a customer may choose aninstance type from a predefined set of instance types. As anotherexample, a customer may specify the desired resources of an instancetype and/or requirements of a workload that the instance will run, andthe instance type selection functionality may select an instance typebased on such a specification.

The data plane 221 can also include one or more block store servers,which can include persistent storage for storing volumes of customerdata, as well as software for managing these volumes. These block storeservers can support a managed block storage service of the cloudprovider network. The managed block storage service may be part of thecontrol plane 218, allowing customers to issue commands via theinterface 206 (e.g., an API) to create and manage volumes for theirapplications running on compute instances. The block store serversinclude one or more servers on which data is stored as blocks. A blockis a sequence of bytes or bits, usually containing some whole number ofrecords, having a maximum length of the block size. Blocked data isnormally stored in a data buffer and read or written a whole block at atime. In general, a volume can correspond to a logical collection ofdata, such as a set of data maintained on behalf of a user. Uservolumes, which can be treated as an individual hard drive ranging forexample from 1 GB to 1 terabyte (TB) or more in size, are made of one ormore blocks stored on the block store servers. Although treated as anindividual hard drive, it will be appreciated that a volume may bestored as one or more virtualized devices implemented on one or moreunderlying physical host devices. Volumes may be partitioned a smallnumber of times (e.g., up to 16) with each partition hosted by adifferent host. The data of the volume may be replicated betweenmultiple devices within the cloud provider network, in order to providemultiple replicas of the volume (where such replicas may collectivelyrepresent the volume on the computing system). Replicas of a volume in adistributed computing system can beneficially provide for automaticfailover and recovery, for example by allowing the user to access eithera primary replica of a volume or a secondary replica of the volume thatis synchronized to the primary replica at a block level, such that afailure of either the primary or secondary replica does not inhibitaccess to the information of the volume. The role of the primary replicacan be to facilitate reads and writes (sometimes referred to as “inputoutput operations,” or simply “I/O operations”) at the volume, and topropagate any writes to the secondary (preferably synchronously in theI/O path, although asynchronous replication can also be used). Thesecondary replica can be updated synchronously with the primary replicaand provide for seamless transition during failover operations, wherebythe secondary replica assumes the role of the primary replica, andeither the former primary is designated as the secondary or a newreplacement secondary replica is provisioned. Although certain examplesherein discuss a primary replica and a secondary replica, it will beappreciated that a logical volume can include multiple secondaryreplicas. A compute instance can virtualize its I/O to a volume by wayof a client. The client represents instructions that enable a computeinstance to connect to, and perform I/O operations at, a remote datavolume (e.g., a data volume stored on a physically separate computingdevice accessed over a network). The client may be implemented on anoffload card of a server that includes the processing units (e.g., CPUsor GPUs) of the compute instance.

The data plane 221 can also include one or more object store servers,which represent another type of storage within the cloud providernetwork 203. The object storage servers include one or more servers onwhich data is stored as objects within resources referred to as bucketsand can be used to support a managed object storage service of the cloudprovider network 203. Each object typically includes the data beingstored, a variable amount of metadata that enables various capabilitiesfor the object storage servers with respect to analyzing a storedobject, and a globally unique identifier or key that can be used toretrieve the object. Each bucket is associated with a given useraccount. Customers can store as many objects as desired within theirbuckets, can write, read, and delete objects in their buckets, and cancontrol access to their buckets and the objects contained therein.Further, in embodiments having a number of different object storageservers distributed across different ones of the regions describedabove, users can choose the region (or regions) where a bucket isstored, for example to optimize for latency. Customers may use bucketsto store objects of a variety of types, including machine images thatcan be used to launch VMs, and snapshots that represent a point-in-timeview of the data of a volume.

A provider substrate extension 224 (“PSE”) provides resources andservices of the cloud provider network 203 within a separate network,such as a telecommunications network, thereby extending functionality ofthe cloud provider network 203 to new locations (e.g., for reasonsrelated to latency in communications with customer devices, legalcompliance, security, etc.). In some implementations, a PSE 224 can beconfigured to provide capacity for cloud-based workloads to run withinthe telecommunications network. In some implementations, a PSE 224 canbe configured to provide the core and/or RAN functions of thetelecommunications network, and may be configured with additionalhardware (e.g., radio access hardware). Some implementations may beconfigured to allow for both, for example by allowing capacity unused bycore and/or RAN functions to be used for running cloud-based workloads.

As indicated, such provider substrate extensions 224 can include cloudprovider network-managed provider substrate extensions 227 (e.g., formedby servers located in a cloud provider-managed facility separate fromthose associated with the cloud provider network 203), communicationsservice provider substrate extensions 230 (e.g., formed by serversassociated with communications service provider facilities),customer-managed provider substrate extensions 233 (e.g., formed byservers located on-premise in a customer or partner facility), amongother possible types of substrate extensions.

As illustrated in the example provider substrate extension 224, aprovider substrate extension 224 can similarly include a logicalseparation between a control plane 236 and a data plane 239,respectively extending the control plane 218 and data plane 221 of thecloud provider network 203. The provider substrate extension 224 may bepre-configured, e.g. by the cloud provider network operator, with anappropriate combination of hardware with software and/or firmwareelements to support various types of computing-related resources, and todo so in a manner that mirrors the experience of using the cloudprovider network 203. For example, one or more provider substrateextension location servers can be provisioned by the cloud provider fordeployment within a provider substrate extension 224. As describedabove, the cloud provider network 203 may offer a set of predefinedinstance types, each having varying types and quantities of underlyinghardware resources. Each instance type may also be offered in varioussizes. In order to enable customers to continue using the same instancetypes and sizes in a provider substrate extension 224 as they do in theregion, the servers can be heterogeneous servers. A heterogeneous servercan concurrently support multiple instance sizes of the same type andmay be also reconfigured to host whatever instance types are supportedby its underlying hardware resources. The reconfiguration of theheterogeneous server can occur on-the-fly using the available capacityof the servers, that is, while other VMs are still running and consumingother capacity of the provider substrate extension location servers.This can improve utilization of computing resources within the edgelocation by allowing for better packing of running instances on servers,and also provides a seamless experience regarding instance usage acrossthe cloud provider network 203 and the cloud provider network-managedprovider substrate extension 227.

The provider substrate extension servers can host one or more computeinstances. Compute instances can be VMs, or containers that package upcode and all its dependencies so an application can run quickly andreliably across computing environments (e.g., including VMs andmicroVMs). In addition, the servers may host one or more data volumes,if desired by the customer. In the region of a cloud provider network203, such volumes may be hosted on dedicated block store servers.However, due to the possibility of having a significantly smallercapacity at a provider substrate extension 224 than in the region, anoptimal utilization experience may not be provided if the providersubstrate extension 224 includes such dedicated block store servers.Accordingly, a block storage service may be virtualized in the providersubstrate extension 224, such that one of the VMs runs the block storesoftware and stores the data of a volume. Similar to the operation of ablock storage service in the region of a cloud provider network 203, thevolumes within a provider substrate extension 224 may be replicated fordurability and availability. The volumes may be provisioned within theirown isolated virtual network within the provider substrate extension224. The compute instances and any volumes collectively make up a dataplane 239 extension of the provider network data plane 221 within theprovider substrate extension 224.

The servers within a provider substrate extension 224 may, in someimplementations, host certain local control plane components, forexample, components that enable the provider substrate extension 224 tocontinue functioning if there is a break in the connection back to thecloud provider network 203. Examples of these components include amigration manager that can move compute instances between providersubstrate extension servers if needed to maintain availability, and akey value data store that indicates where volume replicas are located.However, generally the control plane 236 functionality for a providersubstrate extension 224 will remain in the cloud provider network 203 inorder to allow customers to use as much resource capacity of theprovider substrate extension 224 as possible.

The migration manager may have a centralized coordination component thatruns in the region, as well as local controllers that run on the PSEservers (and servers in the cloud provider's data centers). Thecentralized coordination component can identify target edge locationsand/or target hosts when a migration is triggered, while the localcontrollers can coordinate the transfer of data between the source andtarget hosts. The described movement of the resources between hosts indifferent locations may take one of several forms of migration.Migration refers to moving virtual machine instances (and/or otherresources) between hosts in a cloud computing network, or between hostsoutside of the cloud computing network and hosts within the cloud. Thereare different types of migration including live migration and rebootmigration. During a reboot migration, the customer experiences an outageand an effective power cycle of their virtual machine instance. Forexample, a control plane service can coordinate a reboot migrationworkflow that involves tearing down the current domain on the originalhost and subsequently creating a new domain for the virtual machineinstance on the new host. The instance is rebooted by being shut down onthe original host and booted up again on the new host.

Live migration refers to the process of moving a running virtual machineor application between different physical machines without significantlydisrupting the availability of the virtual machine (e.g., the down timeof the virtual machine is not noticeable by the end user). When thecontrol plane executes a live migration workflow it can create a new“inactive” domain associated with the instance, while the originaldomain for the instance continues to run as the “active” domain. Memory(including any in-memory state of running applications), storage, andnetwork connectivity of the virtual machine are transferred from theoriginal host with the active domain to the destination host with theinactive domain. The virtual machine may be briefly paused to preventstate changes while transferring memory contents to the destinationhost. The control plane can transition the inactive domain to become theactive domain and demote the original active domain to become theinactive domain (sometimes referred to as a “flip”), after which theinactive domain can be discarded.

Techniques for various types of migration involve managing the criticalphase—the time when the virtual machine instance is unavailable to thecustomer—which should be kept as short as possible. In the presentlydisclosed migration techniques this can be especially challenging, asresources are being moved between hosts in geographically separatelocations which may be connected over one or more intermediate networks.For live migration, the disclosed techniques can dynamically determinean amount of memory state data to pre-copy (e.g., while the instance isstill running on the source host) and to post-copy (e.g., after theinstance begins running on the destination host), based for example onlatency between the locations, network bandwidth/usage patterns, and/oron which memory pages are used most frequently by the instance. Further,a particular time at which the memory state data is transferred can bedynamically determined based on conditions of the network between thelocations. This analysis may be performed by a migration managementcomponent in the region, or by a migration management component runninglocally in the source edge location. If the instance has access tovirtualized storage, both the source domain and target domain can besimultaneously attached to the storage to enable uninterrupted access toits data during the migration and in the case that rollback to thesource domain is required.

Server software running at a provider substrate extension 224 may bedesigned by the cloud provider to run on the cloud provider substratenetwork, and this software may be enabled to run unmodified in aprovider substrate extension 224 by using local network manager(s) 242to create a private replica of the substrate network within the edgelocation (a “shadow substrate”). The local network manager(s) 242 canrun on provider substrate extension 224 servers and bridge the shadowsubstrate with the provider substrate extension 224 network, forexample, by acting as a virtual private network (VPN) endpoint orendpoints between the provider substrate extension 224 and the proxies245, 248 in the cloud provider network 203 and by implementing themapping service (for traffic encapsulation and decapsulation) to relatedata plane traffic (from the data plane proxies 248) and control planetraffic (from the control plane proxies 245) to the appropriateserver(s). By implementing a local version of the provider network'ssubstrate-overlay mapping service, the local network manager(s) 242allow resources in the provider substrate extension 224 to seamlesslycommunicate with resources in the cloud provider network 203. In someimplementations, a single local network manager 242 can perform theseactions for all servers hosting compute instances in a providersubstrate extension 224. In other implementations, each of the serverhosting compute instances may have a dedicated local network manager242. In multi-rack edge locations, inter-rack communications can gothrough the local network managers 242, with local network managersmaintaining open tunnels to one another.

Provider substrate extension locations can utilize secure networkingtunnels through the provider substrate extension 224 network to thecloud provider network 203, for example, to maintain security ofcustomer data when traversing the provider substrate extension 224network and any other intermediate network (which may include the publicinternet). Within the cloud provider network 203, these tunnels arecomposed of virtual infrastructure components including isolated virtualnetworks (e.g., in the overlay network), control plane proxies 245, dataplane proxies 248, and substrate network interfaces. Such proxies 245,248 may be implemented as containers running on compute instances. Insome embodiments, each server in a provider substrate extension 224location that hosts compute instances can utilize at least two tunnels:one for control plane traffic (e.g., Constrained Application Protocol(CoAP) traffic) and one for encapsulated data plane traffic. Aconnectivity manager (not shown) within the cloud provider network 203manages the cloud provider network-side lifecycle of these tunnels andtheir components, for example, by provisioning them automatically whenneeded and maintaining them in a healthy operating state. In someembodiments, a direct connection between a provider substrate extension224 location and the cloud provider network 203 can be used for controland data plane communications. As compared to a VPN through othernetworks, the direct connection can provide constant bandwidth and moreconsistent network performance because of its relatively fixed andstable network path.

A control plane (CP) proxy 245 can be provisioned in the cloud providernetwork 203 to represent particular host(s) in an edge location. CPproxies 245 are intermediaries between the control plane 218 in thecloud provider network 203 and control plane targets in the controlplane 236 of provider substrate extension 224. That is, CP proxies 245provide infrastructure for tunneling management API traffic destined forprovider substrate extension servers out of the region substrate and tothe provider substrate extension 224. For example, a virtualizedcomputing service of the cloud provider network 203 can issue a commandto a VMM of a server of a provider substrate extension 224 to launch acompute instance. A CP proxy 245 maintains a tunnel (e.g., a VPN) to alocal network manager 242 of the provider substrate extension. Thesoftware implemented within the CP proxies 245 ensures that onlywell-formed API traffic leaves from and returns to the substrate. CPproxies 245 provide a mechanism to expose remote servers on the cloudprovider substrate while still protecting substrate security materials(e.g., encryption keys, security tokens) from leaving the cloud providernetwork 203. The one-way control plane traffic tunnel imposed by the CPproxies 245 also prevents any (potentially compromised) devices frommaking calls back to the substrate. CP proxies 245 may be instantiatedone-for-one with servers at a provider substrate extension 224 or may beable to manage control plane traffic for multiple servers in the sameprovider substrate extension 224.

A data plane (DP) proxy 248 can also be provisioned in the cloudprovider network 203 to represent particular server(s) in a providersubstrate extension 224. The DP proxy 248 acts as a shadow or anchor ofthe server(s) and can be used by services within the cloud providernetwork 203 to monitor the health of the host (including itsavailability, used/free compute and capacity, used/free storage andcapacity, and network bandwidth usage/availability). The DP proxy 248also allows isolated virtual networks to span provider substrateextensions 224 and the cloud provider network 203 by acting as a proxyfor server(s) in the cloud provider network 203. Each DP proxy 248 canbe implemented as a packet-forwarding compute instance or container. Asillustrated, each DP proxy 248 can maintain a VPN tunnel with a localnetwork manager 242 that manages traffic to the server(s) that the DPproxy 248 represents. This tunnel can be used to send data plane trafficbetween the provider substrate extension server(s) and the cloudprovider network 203. Data plane traffic flowing between a providersubstrate extension 224 and the cloud provider network 203 can be passedthrough DP proxies 248 associated with that provider substrate extension224. For data plane traffic flowing from a provider substrate extension224 to the cloud provider network 203, DP proxies 248 can receiveencapsulated data plane traffic, validate it for correctness, and allowit to enter into the cloud provider network 203. DP proxies 248 canforward encapsulated traffic from the cloud provider network 203directly to a provider substrate extension 224.

Local network manager(s) 242 can provide secure network connectivitywith the proxies 245, 248 established in the cloud provider network 203.After connectivity has been established between the local networkmanager(s) 242 and the proxies 245, 248, customers may issue commandsvia the interface 206 to instantiate compute instances (and/or performother operations using compute instances) using provider substrateextension resources in a manner analogous to the way in which suchcommands would be issued with respect to compute instances hosted withinthe cloud provider network 203. From the perspective of the customer,the customer can now seamlessly use local resources within a providersubstrate extension (as well as resources located in the cloud providernetwork 203, if desired). The compute instances set up on a server at aprovider substrate extension 224 may communicate both with electronicdevices located in the same network, as well as with other resourcesthat are set up in the cloud provider network 203, as desired. A localgateway 251 can be implemented to provide network connectivity between aprovider substrate extension 224 and a network associated with theextension (e.g., a communications service provider network in theexample of a provider substrate extension 230).

There may be circumstances that necessitate the transfer of data betweenthe object storage service and a provider substrate extension (PSE) 224.For example, the object storage service may store machine images used tolaunch VMs, as well as snapshots representing point-in-time backups ofvolumes. The object gateway can be provided on a PSE server or aspecialized storage device, and provide customers with configurable,per-bucket caching of object storage bucket contents in their PSE 224 tominimize the impact of PSE-region latency on the customer's workloads.The object gateway can also temporarily store snapshot data fromsnapshots of volumes in the PSE 224 and then sync with the objectservers in the region when possible. The object gateway can also storemachine images that the customer designates for use within the PSE 224or on the customer's premises. In some implementations, the data withinthe PSE 224 may be encrypted with a unique key, and the cloud providercan limit keys from being shared from the region to the PSE 224 forsecurity reasons. Accordingly, data exchanged between the object storeservers and the object gateway may utilize encryption, decryption,and/or re-encryption in order to preserve security boundaries withrespect to encryption keys or other sensitive data. The transformationintermediary can perform these operations, and a PSE bucket can becreated (on the object store servers) to store snapshot data and machineimage data using the PSE encryption key.

In the manner described above, a PSE 224 forms an edge location, in thatit provides the resources and services of the cloud provider network 203outside of a traditional cloud provider data center and closer tocustomer devices. An edge location, as referred to herein, can bestructured in several ways. In some implementations, an edge locationcan be an extension of the cloud provider network substrate including alimited quantity of capacity provided outside of an availability zone(e.g., in a small data center or other facility of the cloud providerthat is located close to a customer workload and that may be distantfrom any availability zones). Such edge locations may be referred to as“far zones” (due to being far from other availability zones) or “nearzones” (due to being near to customer workloads). A near zone may beconnected in various ways to a publicly accessible network such as theInternet, for example directly, via another network, or via a privateconnection to a region. Although typically a near zone would have morelimited capacity than a region, in some cases a near zone may havesubstantial capacity, for example thousands of racks or more.

In some implementations, an edge location may be an extension of thecloud provider network substrate formed by one or more servers locatedon-premise in a customer or partner facility, wherein such server(s)communicate over a network (e.g., a publicly-accessible network such asthe Internet) with a nearby availability zone or region of the cloudprovider network. This type of substrate extension located outside ofcloud provider network data centers can be referred to as an “outpost”of the cloud provider network. Some outposts may be integrated intocommunications networks, for example as a multi-access edge computing(MEC) site having physical infrastructure spread acrosstelecommunication data centers, telecommunication aggregation sites,and/or telecommunication base stations within the telecommunicationnetwork. In the on-premise example, the limited capacity of the outpostmay be available for use only by the customer who owns the premises (andany other accounts allowed by the customer). In the telecommunicationsexample, the limited capacity of the outpost may be shared amongst anumber of applications (e.g., games, virtual reality applications,healthcare applications) that send data to users of thetelecommunications network.

An edge location can include data plane capacity controlled at leastpartly by a control plane of a nearby availability zone of the providernetwork. As such, an availability zone group can include a “parent”availability zone and any “child” edge locations homed to (e.g.,controlled at least partly by the control plane of) the parentavailability zone. Certain limited control plane functionality (e.g.,features that require low latency communication with customer resources,and/or features that enable the edge location to continue functioningwhen disconnected from the parent availability zone) may also be presentin some edge locations. Thus, in the above examples, an edge locationrefers to an extension of at least data plane capacity that ispositioned at the edge of the cloud provider network, close to customerdevices and/or workloads.

In the example of FIG. 1A, the distributed computing devices 112 (FIG.1A), the centralized computing devices 115 (FIG. 1A), and the corecomputing devices 118 (FIG. 1A) may be implemented as provider substrateextensions 224 of the cloud provider network 203. The installation orsiting of provider substrate extensions 224 within a communicationnetwork 100 can vary subject to the particular network topology orarchitecture of the communication network 100. Provider substrateextensions 224 can generally be connected anywhere the communicationnetwork 100 can break out packet-based traffic (e.g., IP based traffic).Additionally, communications between a given provider substrateextension 224 and the cloud provider network 203 typically securelytransit at least a portion of the communication network 100 (e.g., via asecure tunnel, virtual private network, a direct connection, etc.).

In 5G wireless network development efforts, edge locations may beconsidered a possible implementation of Multi-access Edge Computing(MEC). Such edge locations can be connected to various points within a5G network that provide a breakout for data traffic as part of the UserPlane Function (UPF). Older wireless networks can incorporate edgelocations as well. In 3G wireless networks, for example, edge locationscan be connected to the packet-switched network portion of acommunication network 100, such as to a Serving General Packet RadioServices Support Node (SGSN) or to a Gateway General Packet RadioServices Support Node (GGSN). In 4G wireless networks, edge locationscan be connected to a Serving Gateway (SGW) or Packet Data NetworkGateway (PGW) as part of the core network or evolved packet core (EPC).In some embodiments, traffic between a provider substrate extension 224and the cloud provider network 203 can be broken out of thecommunication network 100 without routing through the core network.

In some embodiments, provider substrate extensions 224 can be connectedto more than one communication network associated with respectivecustomers. For example, when two communication networks of respectivecustomers share or route traffic through a common point, a providersubstrate extension 224 can be connected to both networks. For example,each customer can assign some portion of its network address space tothe provider substrate extension, and the provider substrate extension224 can include a router or gateway that can distinguish trafficexchanged with each of the communication networks 100. For example,traffic destined for the provider substrate extension 224 from onenetwork might have a different destination IP address, source IPaddress, and/or virtual local area network (VLAN) tag than trafficreceived from another network. Traffic originating from the providersubstrate extension to a destination on one of the networks can besimilarly encapsulated to have the appropriate VLAN tag, source IPaddress (e.g., from the pool allocated to the provider substrateextension from the destination network address space) and destination IPaddress.

FIG. 2B depicts an example 253 of cellularization and geographicdistribution of the communication network 100 (FIG. 1) for providinghighly available user plane functions (UPFs). In FIG. 2B, a user device254 communicates with a request router 255 to route a request to one ofa plurality of control plane cells 257 a and 257 b. Each control planecell 257 may include a network service API gateway 260, a network sliceconfiguration 262, a function for network service monitoring 264, siteplanning data 266 (including layout, device type, device quantities,etc. that describe a customer's site requirements), a networkservice/function catalog 268, a function for orchestration 270, and/orother components. The larger control plane can be divided into cells inorder to reduce the likelihood that large scale errors will affect awide range of customers, for example by having one or more cells percustomer, per network, or per region that operate independently.

The network service/function catalog 268 is also referred to as the NFRepository Function (NRF). In a Service Based Architecture (SBA) 5Gnetwork, the control plane functionality and common data repositoriescan be delivered by way of a set of interconnected network functionsbuilt using a microservices architecture. The NRF can maintain a recordof available NF instances and their supported services, allowing otherNF instances to subscribe and be notified of registrations from NFinstances of a given type. The NRF thus can support service discovery byreceipt of discovery requests from NF instances, and details which NFinstances support specific services. The network function orchestrator270 can perform NF lifecycle management including instantiation,scale-out/in, performance measurements, event correlation, andtermination. The network function orchestrator 270 can also onboard newNFs, manage migration to new or updated versions of existing NFs,identify NF sets that are suitable for a particular network slice orlarger network, and orchestrate NFs across different computing devicesand sites that make up the radio-based network 103.

The control plane cell 257 may be in communication with one or more cellsites 272, one or more customer local data centers 274, one or morelocal zones 276, and one or more regional zones 278. The cell sites 272include computing hardware 280 that executes one or more distributedunit (DU) network functions 282. The customer local data centers 274include computing hardware 283 that execute one or more DU or centralunit (CU) network functions 284, a network controller, a UPF 286, one ormore edge applications 287 corresponding to customer workloads, and/orother components.

The local zones 276, which may be in a data center operated by a cloudservice provider, may execute one or more core network functions 288,such as an AMF, an SMF, a network exposure function (NEF) that securelyexposes the services and capabilities of other network functions, aunified data management (UDM) function that manages subscriber data forauthorization, registration, and mobility management. The local zones276 may also execute a UPF 286, a service for metric processing 289, andone or more edge applications 287.

The regional zones 278, which may be in a data center operated by acloud service provider, may execute one or more core network functions288; a UPF 286; an operations support system (OSS) 290 that supportsnetwork management systems, service delivery, service fulfillment,service assurance, and customer care; an internet protocol multimediasubsystem (IMS) 291; a business support system (BSS) 292 that supportsproduct management, customer management, revenue management, and/ororder management; one or more portal applications 293, and/or othercomponents.

In this example, the communication network 100 employs a cellulararchitecture to reduce the blast radius of individual components. At thetop level, the control plane is in multiple control plane cells 257 toprevent an individual control plane failure from impacting alldeployments.

Within each control plane cell 257, multiple redundant stacks can beprovided with the control plane shifting traffic to secondary stacks asneeded. For example, a cell site 272 may be configured to utilize anearby local zone 276 as its default core network. In the event that thelocal zone 276 experiences an outage, the control plane can redirect thecell site 272 to use the backup stack in the regional zone 278. Trafficthat would normally be routed from the internet to the local zone 276can be shifted to endpoints for the regional zones 278. Each controlplane cell 278 can implement a “stateless” architecture that shares acommon session database across multiple sites (such as acrossavailability zones or edge sites).

FIG. 3 illustrates an exemplary cloud provider network 203 includinggeographically dispersed provider substrate extensions 224 (FIG. 2A) (or“edge locations 303”) according to some embodiments. As illustrated, acloud provider network 203 can be formed as a number of regions 306,where a region 306 is a separate geographical area in which the cloudprovider has one or more data centers 309. Each region 306 can includetwo or more availability zones (AZs) connected to one another via aprivate high-speed network such as, for example, a fiber communicationconnection. An availability zone refers to an isolated failure domainincluding one or more data center facilities with separate power,separate networking, and separate cooling relative to other availabilityzones. A cloud provider may strive to position availability zones withina region 306 far enough away from one another such that a naturaldisaster, widespread power outage, or other unexpected event does nottake more than one availability zone offline at the same time. Customerscan connect to resources within availability zones of the cloud providernetwork 203 via a publicly accessible network (e.g., the Internet, acellular communication network, a communication service providernetwork). Transit Centers (TC) are the primary backbone locationslinking customers to the cloud provider network 203 and may beco-located at other network provider facilities (e.g., Internet serviceproviders, telecommunications providers). Each region 306 can operatetwo or more TCs for redundancy. Regions 306 are connected to a globalnetwork which includes private networking infrastructure (e.g., fiberconnections controlled by the cloud service provider) connecting eachregion 306 to at least one other region. The cloud provider network 203may deliver content from points of presence (PoPs) outside of, butnetworked with, these regions 306 by way of edge locations 303 andregional edge cache servers. This compartmentalization and geographicdistribution of computing hardware enables the cloud provider network203 to provide low-latency resource access to customers on a globalscale with a high degree of fault tolerance and stability.

In comparison to the number of regional data centers or availabilityzones, the number of edge locations 303 can be much higher. Suchwidespread deployment of edge locations 303 can provide low-latencyconnectivity to the cloud for a much larger group of end user devices(in comparison to those that happen to be very close to a regional datacenter 309). In some embodiments, each edge location 303 can be peeredto some portion of the cloud provider network 203 (e.g., a parentavailability zone or regional data center). Such peering allows thevarious components operating in the cloud provider network 203 to managethe compute resources of the edge location 303. In some cases, multipleedge locations 303 may be sited or installed in the same facility (e.g.,separate racks of computer systems) and managed by different zones ordata centers 309 to provide additional redundancy. Note that althoughedge locations 303 are typically depicted herein as within acommunication service provider network or a radio-based network 103(FIG. 1A), in some cases, such as when a cloud provider network facilityis relatively close to a communications service provider facility, theedge location 303 can remain within the physical premises of the cloudprovider network 203 while being connected to the communications serviceprovider network via a fiber or other network link.

An edge location 303 can be structured in several ways. In someimplementations, an edge location 303 can be an extension of the cloudprovider network substrate including a limited quantity of capacityprovided outside of an availability zone (e.g., in a small data centeror other facility of the cloud provider that is located close to acustomer workload and that may be distant from any availability zones).Such edge locations 303 may be referred to as local zones (due to beingmore local or proximate to a group of users than traditionalavailability zones). A local zone may be connected in various ways to apublicly accessible network such as the Internet, for example directly,via another network, or via a private connection to a region 306.Although typically a local zone would have more limited capacity than aregion 306, in some cases a local zone may have substantial capacity,for example thousands of racks or more. Some local zones may use similarinfrastructure as typical cloud provider data centers, instead of theedge location 303 infrastructure described herein.

As indicated herein, a cloud provider network 203 can be formed as anumber of regions 306, where each region 306 represents a geographicalarea in which the cloud provider clusters data centers 309. Each region306 can further include multiple (e.g., two or more) availability zones(AZs) connected to one another via a private high-speed network, forexample, a fiber communication connection. An AZ may provide an isolatedfailure domain including one or more data center facilities withseparate power, separate networking, and separate cooling from those inanother AZ. Preferably, AZs within a region 306 are positioned farenough away from one another, such that a same natural disaster (orother failure-inducing event) should not affect or take more than one AZoffline at the same time. Customers can connect to an AZ of the cloudprovider network via a publicly accessible network (e.g., the Internet,a cellular communication network).

The parenting of a given edge location 303 to an AZ or region 306 of thecloud provider network 203 can be based on a number of factors. One suchparenting factor is data sovereignty. For example, to keep dataoriginating from a communication network in one country within thatcountry, the edge locations 303 deployed within that communicationnetwork can be parented to AZs or regions 306 within that country.Another factor is availability of services. For example, some edgelocations 303 may have different hardware configurations, with thepresence or absence of components such as local non-volatile storage forcustomer data (e.g., solid state drives), graphics accelerators, etc.Some AZs or regions 306 might lack the services to exploit thoseadditional resources, thus, an edge location could be parented to an AZor region 306 that supports the use of those resources. Another factoris the latency between the AZ or region 306 and the edge location 303.While the deployment of edge locations 303 within a communicationnetwork has latency benefits, those benefits might be negated byparenting an edge location 303 to a distant AZ or region 306 thatintroduces significant latency for the edge location 303 to regiontraffic. Accordingly, edge locations 303 are often parented to nearby(in terms of network latency) AZs or regions 306.

Additionally, the disclosed service can provide a private zone to runlocal applications within a cloud provider network. This private zonecan be connected to and effectively part of a broader regional zone, andallows the customer to manage the private zone using the same APIs andtools as used in the cloud provider network. Like an availability zone,the private zone can be assigned a virtual private network subnet. AnAPI can be used to create and assign subnets to all zones that thecustomer wishes to use, including the private zone and existing otherzones. A management console may offer a simplified process for creatinga private zone. Virtual machine instances and containers can be launchedin the private zone just as in regional zones. Customer can configure anetwork gateway to define routes, assign IP addresses, set up networkaddress translation (NAT), and so forth. Automatic scaling can be usedto scale the capacity of virtual machine instances or containers asneeded in the private zone. The same management and authentication APIsof the cloud provider network can be used within the private zone. Insome cases, since cloud services available in the regional zone can beaccessed remotely from private zones over a secure connection, thesecloud services can be accessed without having to upgrade or modify thelocal deployment.

With reference to FIG. 4, shown is a networked environment 400 accordingto various embodiments. The networked environment 400 includes acomputing environment 403, one or more client devices 406, one or morepredeployed devices 409, and one or more radio-based networks 103, whichare in data communication with each other via a network 412. The network412 includes, for example, the Internet, intranets, extranets, wide areanetworks (WANs), local area networks (LANs), wired networks, wirelessnetworks, cable networks, satellite networks, or other suitablenetworks, etc., or any combination of two or more such networks.

The computing environment 403 may comprise, for example, a servercomputer or any other system providing computing capacity.Alternatively, the computing environment 403 may employ a plurality ofcomputing devices that may be arranged, for example, in one or moreserver banks or computer banks or other arrangements. Such computingdevices may be located in a single installation or may be distributedamong many different geographical locations. For example, the computingenvironment 403 may include a plurality of computing devices thattogether may comprise a hosted computing resource, a grid computingresource, and/or any other distributed computing arrangement. In somecases, the computing environment 403 may correspond to an elasticcomputing resource where the allotted capacity of processing, network,storage, or other computing-related resources may vary over time. Forexample, the computing environment 403 may correspond to a cloudprovider network 203 (FIG. 2A), where customers are billed according totheir computing resource usage based on a utility computing model.

In some embodiments, the computing environment 403 may correspond to avirtualized private network within a physical network comprising virtualmachine instances executed on physical computing hardware, e.g., by wayof a hypervisor. The virtual machine instances and any containersrunning on these instances may be given network connectivity by way ofvirtualized network components enabled by physical network components,such as routers and switches.

Various applications and/or other functionality may be executed in thecomputing environment 403 according to various embodiments. Also,various data is stored in a data store 415 that is accessible to thecomputing environment 403. The data store 415 may be representative of aplurality of data stores 415 as can be appreciated. The data stored inthe data store 415, for example, is associated with the operation of thevarious applications and/or functional entities described below.

The computing environment 403 as part of a cloud provider networkoffering utility computing services includes computing devices 418 andother types of computing devices 418. The computing devices 418 maycorrespond to different types of computing devices 418 and may havedifferent computing architectures. The computing architectures maydiffer by utilizing processors having different architectures, such asx86, x86_64, ARM, Scalable Processor Architecture (SPARC), PowerPC, andso on. For example, some computing devices 418 may have x86 processors,while other computing devices 418 may have ARM processors. The computingdevices 418 may differ also in hardware resources available, such aslocal storage, graphics processing units (GPUs), machine learningextensions, and other characteristics.

The computing devices 418 may have various forms of allocated computingcapacity 421, which may include virtual machine (VM) instances,containers, serverless functions, and so forth. The VM instances may beinstantiated from a VM image. To this end, customers may specify that avirtual machine instance should be launched in a particular type ofcomputing device 418 as opposed to other types of computing devices 418.In various examples, one VM instance may be executed singularly on aparticular computing device 418, or a plurality of VM instances may beexecuted on a particular computing device 418. Also, a particularcomputing device 418 may execute different types of VM instances, whichmay offer different quantities of resources available via the computingdevice 418. For example, some types of VM instances may offer morememory and processing capability than other types of VM instances.

The components executed on the computing environment 403, for example,include a route advertiser 156, a tunnel control plane 162, one or moreelastic network interfaces 159, one or more tunnel hosts 165, one ormore UPFs 153, one or more route reflectors 168, and other applications,services, processes, systems, engines, or functionality not discussed indetail herein. Each of these components may be executed as allocatedcomputing capacity 421 on computing devices 418 that may be located atcell sites, at customer sites, at local zone data centers, at regiondata centers, and so on.

The data stored in the data store 415 includes, for example, one or morenetwork plans 439, one or more cellular topologies 442, one or morespectrum assignments 445, device data 448, one or more RBN metrics 451,customer billing data 454, radio unit configuration data 457, antennaconfiguration data 460, network function configuration data 463, one ormore network function workloads 466, one or more customer workloads 469,tunnel host data 472, route reflector data 475, and potentially otherdata.

The network plan 439 is a specification of a radio-based network 103 tobe deployed for a customer. For example, a network plan 439 may includepremises locations or geographic areas to be covered, a number of cells,device identification information and permissions, a desired maximumnetwork latency, a desired bandwidth or network throughput for one ormore classes of devices, one or more quality of service parameters forapplications or services, and/or other parameters that can be used tocreate a radio-based network 103. A customer may manually specify one ormore of these parameters via a user interface. One or more of theparameters may be prepopulated as default parameters. In some cases, anetwork plan 439 may be generated for a customer based at least in parton automated site surveys using unmanned aerial vehicles. Values of theparameters that define the network plan 439 may be used as a basis for acloud service provider billing the customer under a utility computingmodel. For example, the customer may be billed a higher amount for lowerlatency targets and/or higher bandwidth targets in a service-levelagreement (SLA), and the customer can be charged on a per-device basis,a per-cell basis, based on a geographic area served, based on spectrumavailability, etc.

The cellular topology 442 includes an arrangement of a plurality ofcells for a customer that takes into account reuse of frequency spectrumwhere possible given the location of the cells. The cellular topology442 may be automatically generated given a site survey. In some cases,the number of cells in the cellular topology 442 may be automaticallydetermined based on a desired geographic area to be covered,availability of backhaul connectivity at various sites, signalpropagation, available frequency spectrum, and/or on other parameters.

The spectrum assignments 445 include frequency spectrum that isavailable to be allocated for radio-based networks 103, as well asfrequency spectrum that is current allocated to radio-based networks103. The frequency spectrum may include spectrum that is publiclyaccessible without restriction, spectrum that is individually owned orleased by customers, spectrum that is owned or leased by the provider,spectrum that is free to use but requires reservation, and so on.

The device data 448 corresponds to data describing wireless devices 106(FIG. 1A) that are permitted to connect to the radio-based network 103.This device data 448 includes corresponding users, account information,billing information, data plan, permitted applications or uses, anindication of whether the wireless device 106 is mobile or fixed, alocation, a current cell, a network address, device identifiers (e.g.,International Mobile Equipment Identity (IMEI) number, Equipment SerialNumber (ESN), Media Access Control (MAC) address, Subscriber IdentityModule (SIM) number, etc.), and so on.

The RBN metrics 451 include various metrics or statistics that indicatethe performance or health of the radio-based network 103. Such RBNmetrics 451 may include bandwidth metrics, dropped packet metrics,signal strength metrics, latency metrics, and so on. The RBN metrics 451may be aggregated on a per-device basis, a per-cell basis, aper-customer basis, etc.

The customer billing data 454 specifies charges that the customer is toincur for the operation of the radio-based network 103 for the customerby the provider. The charges may include fixed costs based uponequipment deployed to the customer and/or usage costs based uponutilization. In some cases, the customer may purchase the equipmentup-front and may be charged only for bandwidth or backend network costs.In other cases, the customer may incur no up-front costs and may becharged purely based on utilization. With the equipment being providedto the customer based on a utility computing model, the cloud serviceprovider may choose an optimal configuration of equipment in order tomeet customer target performance metrics while avoiding overprovisioningof unnecessary hardware.

The radio unit configuration data 457 may correspond to configurationsettings for radio units deployed in radio-based networks 103. Suchsettings may include frequencies to be used, protocols to be used,modulation parameters, bandwidth, network routing and/or backhaulconfiguration, and so on.

The antenna configuration data 460 may correspond to configurationsettings for antennas, to include frequencies to be used, azimuth,vertical or horizontal orientation, beam tilt, and/or other parametersthat may be controlled automatically (e.g., by network-connected motorsand controls on the antennas) or manually by directing a user to mountthe antenna in a certain way or make a physical change to the antenna.

The network function configuration data 463 corresponds to configurationsettings that configure the operation of various network functions forthe radio-based network 103. In various embodiments, the networkfunctions may be deployed in VM instances located in computing devices418 that are at cell sites, at customer aggregation sites, or in datacenters remotely located from the customer. Non-limiting examples ofnetwork functions may include an access and mobility managementfunction, a session management function, a user plane function, a policycontrol function, an authentication server function, a unified datamanagement function, an application function, a network exposurefunction, a network function repository, a network slice selectionfunction, and/or others. The network function workloads 466 correspondto machine images, containers, or functions to be launched in theallocated computing capacity 421 to perform one or more of the networkfunctions.

The customer workloads 469 correspond to machine images, containers, orfunctions of the customer that may be executed alongside or in place ofthe network function workloads 466 in the allocated computing capacity421. For example, the customer workloads 469 may provide or support acustomer application or service.

The tunnel host data 472 includes configuration data for tunnel hosts165 and routing information. The route reflector data 475 includesconfiguration data for route reflectors 168 and routing informationgathered from the UPFs 153.

The client device 406 is representative of a plurality of client devices406 that may be coupled to the network 412. The client device 406 maycomprise, for example, a processor-based system such as a computersystem. Such a computer system may be embodied in the form of a desktopcomputer, a laptop computer, personal digital assistants, cellulartelephones, smartphones, set-top boxes, music players, web pads, tabletcomputer systems, game consoles, electronic book readers, smartwatches,head mounted displays, voice interface devices, or other devices. Theclient device 406 may include a display comprising, for example, one ormore devices such as liquid crystal display (LCD) displays, gasplasma-based flat panel displays, organic light emitting diode (OLED)displays, electrophoretic ink (E ink) displays, LCD projectors, or othertypes of display devices, etc.

The client device 406 may be configured to execute various applicationssuch as a client application 436 and/or other applications. The clientapplication 436 may be executed in a client device 406, for example, toaccess network content served up by the computing environment 403 and/orother servers, thereby rendering a user interface on the display. Tothis end, the client application 436 may comprise, for example, abrowser, a dedicated application, etc., and the user interface maycomprise a network page, an application screen, etc. The client device406 may be configured to execute applications beyond the clientapplication 436 such as, for example, email applications, socialnetworking applications, word processors, spreadsheets, and/or otherapplications.

Referring next to FIG. 5, shown is a flowchart that provides one exampleof the operation of a portion of the tunnel control plane 162 accordingto various embodiments. It is understood that the flowchart of FIG. 5provides merely an example of the many different types of functionalarrangements that may be employed to implement the operation of theportion of the tunnel control plane 162 as described herein. As analternative, the flowchart of FIG. 5 may be viewed as depicting anexample of elements of a method implemented in the computing environment403 (FIG. 4) according to one or more embodiments.

Beginning with box 503, the tunnel control plane 162 determines networkinformation for the radio-based network 103 (FIG. 4) and the associatedcore network from the network plan 439 (FIG. 4). The network informationmay include information about various network function workloads 466(FIG. 4) such as user plane functions (UPFs) and other data-processingnetwork functions that may be implemented in the allocated computingcapacity 421 (FIG. 4), ranges of network addresses to be routed to thosenetwork function workloads 466, and other information.

In box 506, the tunnel control plane 162 configures a route advertiser156 (FIG. 4) to advertise routes for the network addresses of theradio-based network 103. The route advertiser 156 may advertise theroutes to one or more other autonomous systems of the network 121 (FIG.1B). The routes may point to one or more network addresses of an elasticnetwork interface 159 (FIG. 4), which may be implemented by one or morecomputing devices 418 (FIG. 4) to flexibly exchange network traffic withthe network 121 using software-defined networking. It is noted that thenetwork addresses may include multiple ranges (or prefixes) of networkaddresses. The route advertiser 156 may advertise routes to differentelastic network interfaces 159 based upon geographic proximity todata-processing network function instances in different regions 306(FIG. 3).

In box 509, the tunnel control plane 162 launches one or more routereflectors 168 (FIG. 4) in the computing environment 403. In some cases,the route reflectors 168 may be launched at cell sites, edge locations,local zone data centers, region data centers, or other locations. In box512, the tunnel control plane 162 configures the route reflectors 168via an API call or through configuration data in the route reflectordata 475 (FIG. 4). The route reflectors 168 are configured to receiverouting information from the UPFs 153 (FIG. 4) or other data-processingnetwork functions and to publish the routing information to the tunnelhosts 165 (FIG. 4). In some cases, there may be multiple routereflectors 168 configured to receive routing information from each ofmultiple UPFs and then to publish the routing information to multipletunnel hosts 165. The tunnel control plane 162 may scale up or down thequantity of route reflectors 168.

In box 515, the tunnel control plane 162 launches one or more tunnelhosts 165 in the computing environment 403. In some cases, the tunnelhosts 165 may be launched at cell sites, edge locations, local zone datacenters, region data centers, or other locations. In box 518, the tunnelcontrol plane 162 configures the tunnel hosts 165 via an API call orthrough configuration data in the tunnel host data 472 (FIG. 4). Thetunnel hosts 165 are configured to receive inbound network traffic fromthe external network 121 via the elastic network interface 159 and toconsistently route and/or forward the network traffic to the same UPF153 or other data-processing network function on a per-flow basis. Thetunnel control plane 162 may scale up or down the quantity of tunnelhosts 165.

In box 521, the tunnel control plane 162 configures the elastic networkinterface 159 to route specific flows and/or network address ranges toparticular tunnel hosts 165 in a consistent way. In this way, the sameflows can be assigned to the same tunnel host 165. The tunnel controlplane 162 may also reconfigure the elastic network interface 159 todirect traffic to additional or fewer tunnel hosts 165 if the quantityof tunnel hosts 165 is scaled up or down. Thereafter, the operation ofthe portion of the tunnel control plane 162 ends.

Moving on to FIG. 6, shown is a flowchart that provides one example ofthe operation of a portion of the route reflector 168 according tovarious embodiments. It is understood that the flowchart of FIG. 6provides merely an example of the many different types of functionalarrangements that may be employed to implement the operation of theportion of the route reflector 168 as described herein. As analternative, the flowchart of FIG. 6 may be viewed as depicting anexample of elements of a method implemented in the computing environment403 (FIG. 4) according to one or more embodiments.

Beginning with box 603, the route reflector 168 receives routinginformation from one or more UPFs 153 (FIG. 4) or another type ofdata-processing network function. The routing information may include amapping of particular network address ranges to particular UPFs 153. Forexample, the routing information may be advertised by the UPFs 153 usingBGP, open shortest path first (OSPF), or another protocol. The routereflector 168 may receive routing information from multiple UPFs 153,and UPFs 153 may advertise routes as being primary or backup routes. Therouting information may be updated over time. In some examples, theroute reflector 168 communicates via an elastic network interface 159(FIG. 4) to a private network, or virtual private network, operated bythe customer and including the UPFs 153. The routing may be determinedbased at least in part on geographic proximity or network topologicalproximity, and UPFs 153 may be located in different regions 306 (FIG.3).

In box 606, the route reflector 168 may send the routing information toone or more tunnel hosts 165 (FIG. 4). In some implementations, theroute reflector 168 may send the same routing information to multipletunnel hosts 165 or only the tunnel hosts 165 that are configured toroute the specific ranges of network addresses. In some cases, multipleroute reflectors 168 may operate in parallel to obtain this routinginformation. The route reflector 168 in some scenarios may send therouting information to the tunnel host 165 in response to a long pollfrom the tunnel host 165.

In box 609, the route reflector 168 may advertise in the customer'sprivate network a default route to reach the external network 121 (FIG.1B) through a particular tunnel host 165 that handles the networktraffic for the customer's private network. In this way, outboundnetwork traffic, such as from the UPFs 153 or other data-processingnetwork functions, can be routed through the tunnel hosts 165 to theexternal network 121. Thereafter, the operation of the portion of theroute reflector 168 ends.

Continuing to FIG. 7, shown is a flowchart that provides one example ofthe operation of a portion of the tunnel host 165 according to variousembodiments. It is understood that the flowchart of FIG. 7 providesmerely an example of the many different types of functional arrangementsthat may be employed to implement the operation of the portion of thetunnel host 165 as described herein. As an alternative, the flowchart ofFIG. 7 may be viewed as depicting an example of elements of a methodimplemented in the computing environment 403 (FIG. 4) according to oneor more embodiments.

Beginning with box 703, the tunnel host 165 receives routing informationfrom one or more route reflectors 168 (FIG. 4). This information mayindicate ranges or prefixes of network addresses that are to beforwarded to specific UPFs 153 (FIG. 4) or other data-processing networkfunctions for processing and eventual forwarding to user devices on theradio-based network 103 (FIG. 4). In box 706, the tunnel host 165receives inbound network traffic from an external network 121 (FIG. 1A)via an elastic network interface 159 (FIG. 4). For example, the elasticnetwork interface 159 may be configured by the tunnel control plane 162(FIG. 4) to direct certain flows or ranges of network addresses toparticular tunnel hosts 165.

In box 709, the tunnel host 165 consistently routes inbound networktraffic to a particular data-processing network function instance, suchas a UPF 153. A goal may be to always route specific flows or networkaddresses to the same UPF 153. The routing may include forwarding thenetwork traffic via an elastic network interface 159 into a privatenetwork including the UPF 153 and operated by the customer. The routingmay be determined based at least in part on geographic proximity ornetwork topological proximity, and UPFs 153 may be located in differentregions 306 (FIG. 3).

In box 712, the tunnel host 165 receives outbound network traffic fromthe private network and the particular data-processing network functioninstance, such as the UPF 153. In box 715, the tunnel host 165 routesthe outbound network traffic to the external network 121 via the elasticnetwork interface 159.

In box 718, the tunnel host 165 may determine that a particulardata-processing network function instance, or UPF 153, is unavailable orhas a problem. For example, periodic health checks on the UPF 153 mayfail, or network traffic forwarded to the UPF 153 may be dropped orunacknowledged. The tunnel control plane 162 in some instances mayreceive signals indicating that the UPF 153 is unavailable or has aproblem. In some cases, the tunnel control plane 162 may receive signalsthat traffic handled by a UPF 153 is to be migrated to another UPF 153.The change in assignments may be discovered by and/or communicated bythe route reflectors 168.

In box 721, the tunnel host 165 determines a different data-processingnetwork function instance from the backup route information communicatedby the route reflectors 168. For example, the tunnel host 165 mayidentify a different UPF 153 that is capable of processing the networktraffic for the range of network addresses. In some cases, multiple UPFs153 may be identified, each processing a portion of the range of networkaddresses, potentially in conjunction with other ranges of networkaddresses.

In box 724, the tunnel host 165 routes subsequent inbound networktraffic to the different data-processing network function instance ordifferent UPF 153. In some scenarios, the tunnel host 165 may graduallyroute the subsequent inbound network traffic to the differentdata-processing network function instance or different UPF 153 in orderto draw down the traffic on the first data-processing network functioninstance or UPF 153. For example, new connections or flows might berouted to the different UPF 153, while existing connections or flowsmight continue be routed to the previous UPF 153 indefinitely or for aperiod of time.

In some embodiments, the tunnel host 165 communicates with an individualdata-processing network function instance to obtain state informationfor that data-processing network function instance. This stateinformation may include various types of state information for a flow(e.g., latency metrics, bandwidth metrics, metrics computed on thepayload of the data packets, etc.). The tunnel host 165 may then providestate information to the different data-processing network functioninstance when subsequent data flows are rerouted to the differentdata-processing network function instance. In various embodiments, thestate information may be retrieved from, or provided to, data-processingnetwork function instances via an API or a data store.

In box 727, the tunnel host 165 receives outbound network traffic fromthe different data-processing network function instance or UPF 153. Inbox 730, the tunnel host 165 routes the outbound network traffic to theexternal network 121 via the elastic network interface 159. Thereafter,the operation of the portion of the tunnel host 165 ends.

With reference to FIG. 8, shown is a schematic block diagram of thecomputing environment 403 according to an embodiment of the presentdisclosure. The computing environment 403 includes one or more computingdevices 800. Each computing device 800 includes at least one processorcircuit, for example, having a processor 803 and a memory 806, both ofwhich are coupled to a local interface 809. To this end, each computingdevice 800 may comprise, for example, at least one server computer orlike device. The local interface 809 may comprise, for example, a databus with an accompanying address/control bus or other bus structure ascan be appreciated.

Stored in the memory 806 are both data and several components that areexecutable by the processor 803. In particular, stored in the memory 806and executable by the processor 803 are the route advertiser 156, one ormore UPFs 153, the tunnel control plane 162, one or more routereflectors 168, one or more elastic network interfaces 159, one or moretunnel hosts 165, and potentially other applications. Also stored in thememory 806 may be a data store 415 and other data. In addition, anoperating system may be stored in the memory 806 and executable by theprocessor 803.

It is understood that there may be other applications that are stored inthe memory 806 and are executable by the processor 803 as can beappreciated. Where any component discussed herein is implemented in theform of software, any one of a number of programming languages may beemployed such as, for example, C, C++, C#, Objective C, Java®,JavaScript®, Perl, PHP, Visual Basic®, Python®, Ruby, Flash®, or otherprogramming languages.

A number of software components are stored in the memory 806 and areexecutable by the processor 803. In this respect, the term “executable”means a program file that is in a form that can ultimately be run by theprocessor 803. Examples of executable programs may be, for example, acompiled program that can be translated into machine code in a formatthat can be loaded into a random access portion of the memory 806 andrun by the processor 803, source code that may be expressed in properformat such as object code that is capable of being loaded into a randomaccess portion of the memory 806 and executed by the processor 803, orsource code that may be interpreted by another executable program togenerate instructions in a random access portion of the memory 806 to beexecuted by the processor 803, etc. An executable program may be storedin any portion or component of the memory 806 including, for example,random access memory (RAM), read-only memory (ROM), hard drive,solid-state drive, USB flash drive, memory card, optical disc such ascompact disc (CD) or digital versatile disc (DVD), floppy disk, magnetictape, or other memory components.

The memory 806 is defined herein as including both volatile andnonvolatile memory and data storage components. Volatile components arethose that do not retain data values upon loss of power. Nonvolatilecomponents are those that retain data upon a loss of power. Thus, thememory 806 may comprise, for example, random access memory (RAM),read-only memory (ROM), hard disk drives, solid-state drives, USB flashdrives, memory cards accessed via a memory card reader, floppy disksaccessed via an associated floppy disk drive, optical discs accessed viaan optical disc drive, magnetic tapes accessed via an appropriate tapedrive, and/or other memory components, or a combination of any two ormore of these memory components. In addition, the RAM may comprise, forexample, static random access memory (SRAM), dynamic random accessmemory (DRAM), or magnetic random access memory (MRAM) and other suchdevices. The ROM may comprise, for example, a programmable read-onlymemory (PROM), an erasable programmable read-only memory (EPROM), anelectrically erasable programmable read-only memory (EEPROM), or otherlike memory device.

Also, the processor 803 may represent multiple processors 803 and/ormultiple processor cores and the memory 806 may represent multiplememories 806 that operate in parallel processing circuits, respectively.In such a case, the local interface 809 may be an appropriate networkthat facilitates communication between any two of the multipleprocessors 803, between any processor 803 and any of the memories 806,or between any two of the memories 806, etc. The local interface 809 maycomprise additional systems designed to coordinate this communication,including, for example, performing load balancing. The processor 803 maybe of electrical or of some other available construction.

Although the route advertiser 156, the UPFs 153, the tunnel controlplane 162, the route reflectors 168, the elastic network interfaces 159,the tunnel hosts 165, and other various systems described herein may beembodied in software or code executed by general purpose hardware asdiscussed above, as an alternative the same may also be embodied indedicated hardware or a combination of software/general purpose hardwareand dedicated hardware. If embodied in dedicated hardware, each can beimplemented as a circuit or state machine that employs any one of or acombination of a number of technologies. These technologies may include,but are not limited to, discrete logic circuits having logic gates forimplementing various logic functions upon an application of one or moredata signals, application specific integrated circuits (ASICs) havingappropriate logic gates, field-programmable gate arrays (FPGAs), orother components, etc. Such technologies are generally well known bythose skilled in the art and, consequently, are not described in detailherein.

The flowcharts of FIGS. 5-7 show the functionality and operation of animplementation of portions of the tunnel control plane 162, the routereflectors 168, and the tunnel hosts 165. If embodied in software, eachblock may represent a module, segment, or portion of code that comprisesprogram instructions to implement the specified logical function(s). Theprogram instructions may be embodied in the form of source code thatcomprises human-readable statements written in a programming language ormachine code that comprises numerical instructions recognizable by asuitable execution system such as a processor 803 in a computer systemor other system. The machine code may be converted from the source code,etc. If embodied in hardware, each block may represent a circuit or anumber of interconnected circuits to implement the specified logicalfunction(s).

Although the flowcharts of FIGS. 5-7 show a specific order of execution,it is understood that the order of execution may differ from that whichis depicted. For example, the order of execution of two or more blocksmay be scrambled relative to the order shown. Also, two or more blocksshown in succession in FIGS. 5-7 may be executed concurrently or withpartial concurrence. Further, in some embodiments, one or more of theblocks shown in FIGS. 5-7 may be skipped or omitted. In addition, anynumber of counters, state variables, warning semaphores, or messagesmight be added to the logical flow described herein, for purposes ofenhanced utility, accounting, performance measurement, or providingtroubleshooting aids, etc. It is understood that all such variations arewithin the scope of the present disclosure.

Also, any logic or application described herein, including the routeadvertiser 156, the UPFs 153, the tunnel control plane 162, the routereflectors 168, the elastic network interfaces 159, and the tunnel hosts165, that comprises software or code can be embodied in anynon-transitory computer-readable medium for use by or in connection withan instruction execution system such as, for example, a processor 803 ina computer system or other system. In this sense, the logic maycomprise, for example, statements including instructions anddeclarations that can be fetched from the computer-readable medium andexecuted by the instruction execution system. In the context of thepresent disclosure, a “computer-readable medium” can be any medium thatcan contain, store, or maintain the logic or application describedherein for use by or in connection with the instruction executionsystem.

The computer-readable medium can comprise any one of many physical mediasuch as, for example, magnetic, optical, or semiconductor media. Morespecific examples of a suitable computer-readable medium would include,but are not limited to, magnetic tapes, magnetic floppy diskettes,magnetic hard drives, memory cards, solid-state drives, USB flashdrives, or optical discs. Also, the computer-readable medium may be arandom access memory (RAM) including, for example, static random accessmemory (SRAM) and dynamic random access memory (DRAM), or magneticrandom access memory (MRAM). In addition, the computer-readable mediummay be a read-only memory (ROM), a programmable read-only memory (PROM),an erasable programmable read-only memory (EPROM), an electricallyerasable programmable read-only memory (EEPROM), or other type of memorydevice.

Further, any logic or application described herein, including the routeadvertiser 156, the UPFs 153, the tunnel control plane 162, the routereflectors 168, the elastic network interfaces 159, and the tunnel hosts165, may be implemented and structured in a variety of ways. Forexample, one or more applications described may be implemented asmodules or components of a single application. Further, one or moreapplications described herein may be executed in shared or separatecomputing devices or a combination thereof. For example, a plurality ofthe applications described herein may execute in the same computingdevice 800, or in multiple computing devices 800 in the same computingenvironment 403.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to present that an item, term, etc., may beeither X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z).Thus, such disjunctive language is not generally intended to, and shouldnot, imply that certain embodiments require at least one of X, at leastone of Y, or at least one of Z to each be present.

It should be emphasized that the above-described embodiments of thepresent disclosure are merely possible examples of implementations setforth for a clear understanding of the principles of the disclosure.Many variations and modifications may be made to the above-describedembodiment(s) without departing substantially from the spirit andprinciples of the disclosure. All such modifications and variations areintended to be included herein within the scope of this disclosure andprotected by the following claims.

Therefore, the following is claimed:
 1. A system, comprising: an elasticnetwork interface that receives all inbound network traffic from anexternal network destined for a radio-based network, including inboundnetwork traffic directed to a plurality of ranges of network addresses;a plurality of tunnel hosts, individual tunnel hosts being configured toconsistently route network traffic corresponding to a respective rangeof the plurality of ranges of network addresses to a respective userplane function (UPF) of a plurality of UPFs that process the networktraffic before forwarding the network traffic to a plurality of userdevices on the radio-based network; and a plurality of route reflectors,individual route reflectors of the plurality of route reflectorsreceiving routing information from the plurality of UPFs and forwardingthe routing information to the plurality of tunnel hosts.
 2. The systemof claim 1, wherein the routing information includes a backup routecorresponding to a backup UPF of the plurality of UPFs, the backup routecorresponding to a particular range of the plurality of ranges ofnetwork addresses that is normally routed to another UPF of theplurality of UPFs.
 3. The system of claim 2, wherein the backup UPF isat a first edge location, and the other UPF is at a second edgelocation.
 4. The system of claim 2, wherein the backup UPF is at aregional data center location, and the other UPF is at an edge location.5. The system of claim 1, further comprising a route advertiser, whereinwhen executed the route advertiser further causes at least one computingdevice to at least: advertise a route to the plurality of ranges ofnetwork addresses to the external network, the route being to theelastic network interface.
 6. The system of claim 1, further comprisinga control plane for the radio-based network that is cellularized into aplurality of control plane cells that operate independently.
 7. Asystem, comprising: at least one computing device; an elastic networkinterface that receives all inbound network traffic from an externalnetwork destined for a radio-based network, including inbound networktraffic directed to a first range of network addresses and a secondrange of network addresses; and a tunnel host executable in the at leastone computing device, wherein when executed the tunnel host causes theat least one computing device to at least: receive network traffic fromthe external network directed at the first range of network addressescorresponding to a plurality of user devices on the radio-based networkvia the elastic network interface; determine a first instance of aplurality of instances of a data-processing network function, the firstinstance handling the first range of network addresses; and forward thenetwork traffic to the first instance.
 8. The system of claim 7, furthercomprising another tunnel host, wherein when executed the other tunnelhost further causes the at least one computing device to at least:receive other network traffic from the external network directed at thesecond range of network addresses corresponding to another plurality ofuser devices on the radio-based network via the elastic networkinterface; determine a second instance of the plurality of instances ofthe data-processing network function, the second instance handling thesecond range of network addresses; and forward the other network trafficto the second instance.
 9. The system of claim 7, further comprising atunnel control plane, wherein when executed the tunnel control planefurther causes the at least one computing device to at least: launch thetunnel host and another tunnel host in a cloud computing resource;assign the first range of network addresses to the tunnel host; andassign the second range of network addresses to the other tunnel host.10. The system of claim 7, further comprising a route reflector, whereinwhen executed the route reflector further causes the at least onecomputing device to at least: receive routing information from the firstinstance; advertise a route for the first range of network addresses tothe tunnel host; receive other routing information from a secondinstance of the plurality of instances of the data-processing networkfunction; and advertise a backup route for the first range of networkaddresses to the tunnel host.
 11. The system of claim 7, wherein whenexecuted the tunnel host further causes the at least one computingdevice to at least: receive outbound network traffic from the firstinstance; and forward the outbound network traffic to the externalnetwork.
 12. The system of claim 7, wherein when executed the tunnelhost further causes the at least one computing device to at least:determine that a second instance of the plurality of instances of thedata-processing network function handles at least a portion of the firstrange of network addresses after a configuration change; forward thenetwork traffic to the second instance instead of the first instance;obtain state information regarding the network traffic from the firstinstance; and provide the state information to the second instance. 13.The system of claim 7, wherein the tunnel host is operated by a cloudservice provider, the first instance is on a private network operated bya customer of the cloud service provider, and the customer operates theradio-based network.
 14. The system of claim 7, wherein thedata-processing network function is a user plane function (UPF) toprocess the network traffic before sending the network traffic to theplurality of user devices.
 15. A method, comprising: consistentlyrouting, by a tunnel host executed in at least one computing device,network traffic associated with a range of network addresses in aradio-based network to a first instance of a data-processing networkfunction instead of a second instance of the data-processing networkfunction; detecting a problem with the first instance of thedata-processing network function; and redirecting, by the tunnel host,additional network traffic associated with the range of networkaddresses from the first instance of the data-processing networkfunction to the second instance of the data-processing network function.16. The method of claim 15, further comprising consistently routing, byanother tunnel host executed in the at least one computing device, othernetwork traffic associated with a different range of network addressesin the radio-based network to the second instance of the data-processingnetwork function instead of the first instance of the data-processingnetwork function.
 17. The method of claim 15, further comprising:receiving, by at least one route reflector executed in the at least onecomputing device, routing information indicating that the secondinstance of the data-processing network function handles the range ofnetwork addresses from the second instance of the data-processingnetwork function; and sending, by the at least one route reflector, therouting information to the tunnel host.
 18. The method of claim 17,wherein the routing information comprises border gateway protocol (BGP)advertisements obtained through a BGP peering session between the atleast one route reflector and the second instance of the data-processingnetwork function.
 19. The method of claim 17, further comprisingadvertising, by the at least one route reflector, a default route toreach an external network via the tunnel host.
 20. The method of claim17, wherein the routing information is sent by the at least one routereflector to the tunnel host in response to a poll from the tunnel host.